scholarly journals Methane emissions from lake Onego sediments

2021 ◽  
Vol 937 (3) ◽  
pp. 032021
Author(s):  
I V Morozova ◽  
N A Belkina
Keyword(s):  
Lake Sediments ◽  
Bottom Sediments ◽  
Bottom Water ◽  
Methane Emissions ◽  
Flux Rate ◽  
Human Pressure ◽  
Hydrocarbon Gases ◽  
Climate Oscillations ◽  
Methane Concentrations ◽  
Different Parts

Abstract We studied the methane content in Lake Onego bottom sediments and bottom water and revealed a wide variation of its concentrations among different parts of the lake. Methane concentrations were the highest in the pockmarked area of Petrozavodsk Bay, where hydrocarbon gases rise to the lake bed surface from the depth. Methane emissions from Lake Onego sediments were estimated. We show that in addition to the geological and geomorphological characteristics of the basin, the flux rate depends on how the lake sediments are forming under the uneven human pressure and climate oscillations of today.

scholarly journals Methane oxidation in the waters of a humics-rich boreal lake stimulated by photosynthesis, nitrite, Fe(III) and humics

2021 ◽  
Author(s):  
Sigrid van Grinsven ◽  
Kirsten Oswald ◽  
Bernhard Wehrli ◽  
Corinne Jegge ◽  
Jakob Zopfi ◽  
...  
Keyword(s):  
Surface Water ◽  
Methane Oxidation ◽  
Bottom Water ◽  
Water Concentration ◽  
Eutrophic Lake ◽  
Methane Emissions ◽  
Boreal Lakes ◽  
Boreal Lake ◽  
Methane Concentrations

Abstract. Small boreal lakes are known to contribute significantly to global methane emissions. Lake Lovojärvi is a eutrophic lake in Southern Finland with bottom water methane concentrations up to 2 mM. However, the surface water concentration, and thus the diffusive emission potential, was low (

Sedimentation of Pb-210 in Laurentian Shield Lakes

1984 ◽  
Vol 19 (2) ◽  
pp. 97-109 ◽  
Author(s):  
R.J. Cornett ◽  
L. Chant ◽  
D. Link
Keyword(s):  
Lake Sediments ◽  
Water Column ◽  
Rate Constant ◽  
Bottom Sediments ◽  
Atmospheric Fallout ◽  
Small Lakes ◽  
Fractional Rate ◽  
Total Input ◽  
Shield Lakes ◽  
Annual Flux

Abstract The average annual flux of Pb-210 from the atmosphere to lake surfaces and to the bottom sediments was measured in seven small lakes located on the Laurentian Shield. Direct atmospheric fallout of Pb-210 was 136 ± 16 Bq m-2 a-1 Streams from the lakes' catchments input an additional 5 to 473 Bq m-2 a-1. Only 16 to 80 percent of the total input was found in the lake sediments. The fractional rate constant for Pb-210 sedimentation from the water column ranged from 0.25 to 5.3 per annum.

Isotope and geochemical parameters of hydrocarbon gases in bottom sediments of the shelf of the East Siberian Sea

2016 ◽  
Vol 469 (2) ◽  
pp. 864-866 ◽  
Author(s):  
A. I. Gresov ◽  
N. E. Shakhova ◽  
V. I. Sergiyenko ◽  
A. V. Yatsuk ◽  
I. P. Semiletov
Keyword(s):  
Bottom Sediments ◽  
Hydrocarbon Gases ◽  
Geochemical Parameters ◽  
East Siberian Sea

scholarly journals Organochlorine compounds in subarctic small lakes

2020 ◽  
Vol 66 (2) ◽  
pp. 180-197
Author(s):  
E. S. Kolpakova ◽  
A. V. Velyamidova
Keyword(s):  
Lake Sediments ◽  
Bottom Sediments ◽  
Hydrothermal System ◽  
Atmospheric Transport ◽  
Electron Capture Detection ◽  
Adjacent Area ◽  
Chlorinated Phenols ◽  
Natural Boundary ◽  
Small Lakes ◽  
Lake Ecosystems

The article presents the results of studies of the environmental properties of organochlorines which differ in properties and origin, in the lake ecosystems of the Bolshezemelskaya tundra (Nenets Autonomous Okrug, Russia). The purpose of this study was to evaluate and assess the levels, distribution characteristics and composition of organochlorines in the bottom sediments of small lakes located in the Adzva river basin in Pymvashor natural boundary (the northernmost location of the exit of thermal-mineral springs of the continental Europe) and in the adjacent area, outside this unique subarctic hydrothermal zone.In order to meet this goal, multi-method (hydrochemical, geochemical, etc.) research was carried out using standard generally approved laboratory practices with their adaptation to the study goals. The quantitative content and composition of the target individual organochlorines were determined by gas chromatographic method with electron-capture detection.The presence of chlorophenol compounds and polychlorinated benzenes (including persistent organic pollutants) was shown in the lakes sediments. The influence of specific microclimatic conditions of subarctic hydrothermal system on the composition and distribution of chlorophenol compounds in lake sediments was considered. In the small lake sediment core in Pymvashor natural boundary a reducing trend in the levels of organochlorines with depth has been recorded (conditioned among other things by the lithological features of bottom sediments). The chlorophenol compounds were found at highest concentrations (619.3–765.5 ng/g) in the sediment upper layers, rich in organic matter; chlorophenol composition was represented mainly by chlorinated phenols, most likely of biotic origin. A lower concentration (185.0 ng/g) of chlorophenol compounds of predominantly abiogenic origin was determined in the lake sediments outside hydrothermal system. The presence and levels of persistent organochlorine pollutants (pentachlorophenol 0.1–2.4 ng/g; hexa- and pentachlorobenzenes 0.4–3.6 ng/g) in the lake sediments were associated with long-range atmospheric transport from various origin sources in nearby regions and low-latitude territories.

scholarly journals Total phosphorus and organic matter content in bottom sediments of lake under restoration measures with iron treatment

2010 ◽  
Vol 10 (3-4) ◽  
pp. 139-145 ◽  
Author(s):  
Katarzyna Kowalczewska-Madura ◽  
Renata Dondajewska ◽  
Ryszard Gołdyn
Keyword(s):  
Organic Matter ◽  
Lake Sediments ◽  
Total Phosphorus ◽  
Bottom Sediments ◽  
Organic Matter Content ◽  
Dry Weight ◽  
Matter Content ◽  
Iron Treatment ◽  
Iron Sulphate ◽  
Restoration Measures

Total phosphorus and organic matter content in bottom sediments of lake under restoration measures with iron treatmentRusałka Lake is a shallow, man-made, strongly eutrophicated reservoir, being a place of recreational activities for Poznan citizens. Restoration measures with the use of iron sulphate were conducted in years 2006-2007. Phosphorus and organic matter concentrations in lake sediments were analyzed in years 2005-2007 at two research stations (profundal and littoral) to determine its changes under the influence of restoration. Greater phosphorus concentrations were noted in profundal (max 1.55 mg P g-1dry weight (DW)) than in littoral (max 0.98 mg P g-1DW). An increase of P amount in sediment was observed after iron treatment. Among phosphorus fractions Res-P dominated, i.e. phosphorus biologically unavailable for organisms. Organic matter content reached 23.1% in profundal, while 14.8% in littoral. Its amount decreased in following years.

scholarly journals Simulations of atmospheric methane for Cape Grim, Tasmania, to constrain southeastern Australian methane emissions

2015 ◽  
Vol 15 (1) ◽  
pp. 305-317 ◽  
Author(s):  
Z. M. Loh ◽  
R. M. Law ◽  
K. D. Haynes ◽  
P. B. Krummel ◽  
L. P. Steele ◽  
...  
Keyword(s):  
Climate Models ◽  
Atmospheric Model ◽  
Methane Emissions ◽  
Atmospheric Methane ◽  
Austral Spring ◽  
Southeastern Australia ◽  
Australian Continent ◽  
The Impact ◽  
Methane Concentrations ◽  
Cape Grim

Abstract. This study uses two climate models and six scenarios of prescribed methane emissions to compare modelled and observed atmospheric methane between 1994 and 2007, for Cape Grim, Australia (40.7° S, 144.7° E). The model simulations follow the TransCom-CH4 protocol and use the Australian Community Climate and Earth System Simulator (ACCESS) and the CSIRO Conformal-Cubic Atmospheric Model (CCAM). Radon is also simulated and used to reduce the impact of transport differences between the models and observations. Comparisons are made for air samples that have traversed the Australian continent. All six emission scenarios give modelled concentrations that are broadly consistent with those observed. There are three notable mismatches, however. Firstly, scenarios that incorporate interannually varying biomass burning emissions produce anomalously high methane concentrations at Cape Grim at times of large fire events in southeastern Australia, most likely due to the fire methane emissions being unrealistically input into the lowest model level. Secondly, scenarios with wetland methane emissions in the austral winter overestimate methane concentrations at Cape Grim during wintertime while scenarios without winter wetland emissions perform better. Finally, all scenarios fail to represent a~methane source in austral spring implied by the observations. It is possible that the timing of wetland emissions in the scenarios is incorrect with recent satellite measurements suggesting an austral spring (September–October–November), rather than winter, maximum for wetland emissions.

scholarly journals Using satellites to uncover large methane emissions from landfills

2021 ◽  
Author(s):  
Joannes Maasakkers ◽  
Daniel Varon ◽  
Aldís Elfarsdóttir ◽  
Jason McKeever ◽  
Dylan Jervis ◽  
...  
Keyword(s):  
High Resolution ◽  
Hot Spots ◽  
Buenos Aires ◽  
Methane Emissions ◽  
Emission Sources ◽  
Emission Inventories ◽  
Atmospheric Methane ◽  
Target Mode ◽  
Facility Level ◽  
Methane Concentrations

As atmospheric methane concentrations increase at record pace, it is critical to identify individual emission sources with high potential for mitigation. Landfills are responsible for large methane emissions that can be readily abated but have been sparsely observed. Here we leverage the synergy between satellite instruments with different spatiotemporal coverage and resolution to detect and quantify emissions from individual landfill facilities. We use the global surveying Tropospheric Monitoring Instrument (TROPOMI) to identify large emission hot spots, and then zoom in with high-resolution target-mode observations from the GHGSat instrument suite to identify the responsible facilities and characterize their emissions. Using this ‘tip and cue’ approach, we detect and analyze strongly emitting landfills (3-29 t hr−1) in Buenos Aires (Argentina), Delhi (India), Lahore (Pakistan), and Mumbai (India). We find that city-level emissions are 1.6-2.8 times larger than reported in commonly used emission inventories and that the landfills contribute 5-47% of those emissions. Our work demonstrates how complementary satellites enable global detection, identification, and monitoring of methane super-emitters at the facility-level.

Catabolism of Purified Rat Fibrin(ogen) Plasmin Degradation Products in Rats

1982 ◽  
Vol 48 (01) ◽  
pp. 059-061 ◽  
Author(s):  
W Nieuwenhuizen ◽  
J J Emeis ◽  
A Vermond
Keyword(s):  
Rate Constants ◽  
Degradation Products ◽  
Blood Clearance ◽  
Flux Rate ◽  
Fractional Catabolic Rate ◽  
Catabolic Rate ◽  
Main Fraction ◽  
Fibrinogen Molecule ◽  
Different Parts ◽  
D Dimer

SummaryThe blood clearance of purified plasmin degradation products (X, Y, D-dimer, Dcate, D EGTA, E-fibrin, Ecate and E EGTA) of rat fibrin(ogen) has been studied in a homologous system. Transcapillary flux rate constants, fractional catabolic rate constants and the ratios of intravascular and extravascular pools have been calculated. There are considerable differences in these constants between the two early fibrinogen degradation products X and Y. Also the differences between fibrinogen D and E fragments, derived from different parts of the fibrinogen molecule, are considerable. However, the differences between fibrin fragment D-dimer and fibrinogen fragment Dcate are relatively small. Also the differences between fragments E-fibrin, Ecate and EEGTA are small. The main fraction of all E-fragments is extravascular.

scholarly journals Seasonal and interannual variability in wetland methane emissions simulated by CLM4Me' and CAM-chem and comparisons to observations of concentrations

2015 ◽  
Vol 12 (13) ◽  
pp. 4029-4049 ◽  
Author(s):  
L. Meng ◽  
R. Paudel ◽  
P. G. M. Hess ◽  
N. M. Mahowald
Keyword(s):  
Interannual Variability ◽  
Spatial Patterns ◽  
Methane Emission ◽  
Methane Concentration ◽  
Methane Emissions ◽  
Data Availability ◽  
Latitudinal Gradients ◽  
Atmospheric Methane ◽  
Seasonal And Interannual Variability ◽  
Methane Concentrations

Abstract. Understanding the temporal and spatial variation of wetland methane emissions is essential to the estimation of the global methane budget. Our goal for this study is three-fold: (i) to evaluate the wetland methane fluxes simulated in two versions of the Community Land Model, the Carbon-Nitrogen (CN; i.e., CLM4.0) and the Biogeochemistry (BGC; i.e., CLM4.5) versions using the methane emission model CLM4Me' so as to determine the sensitivity of the emissions to the underlying carbon model; (ii) to compare the simulated atmospheric methane concentrations to observations, including latitudinal gradients and interannual variability so as to determine the extent to which the atmospheric observations constrain the emissions; (iii) to understand the drivers of seasonal and interannual variability in atmospheric methane concentrations. Simulations of the transport and removal of methane use the Community Atmosphere Model with chemistry (CAM-chem) model in conjunction with CLM4Me' methane emissions from both CN and BGC simulations and other methane emission sources from literature. In each case we compare model-simulated atmospheric methane concentration with observations. In addition, we simulate the atmospheric concentrations based on the TransCom wetland and rice paddy emissions derived from a different terrestrial ecosystem model, Vegetation Integrative Simulator for Trace gases (VISIT). Our analysis indicates CN wetland methane emissions are higher in the tropics and lower at high latitudes than emissions from BGC. In CN, methane emissions decrease from 1993 to 2004 while this trend does not appear in the BGC version. In the CN version, methane emission variations follow satellite-derived inundation wetlands closely. However, they are dissimilar in BGC due to its different carbon cycle. CAM-chem simulations with CLM4Me' methane emissions suggest that both prescribed anthropogenic and predicted wetlands methane emissions contribute substantially to seasonal and interannual variability in atmospheric methane concentration. Simulated atmospheric CH4 concentrations in CAM-chem are highly correlated with observations at most of the 14 measurement stations evaluated with an average correlation between 0.71 and 0.80 depending on the simulation (for the period of 1993–2004 for most stations based on data availability). Our results suggest that different spatial patterns of wetland emissions can have significant impacts on Northern and Southern hemisphere (N–S) atmospheric CH4 concentration gradients and growth rates. This study suggests that both anthropogenic and wetland emissions have significant contributions to seasonal and interannual variations in atmospheric CH4 concentrations. However, our analysis also indicates the existence of large uncertainties in terms of spatial patterns and magnitude of global wetland methane budgets, and that substantial uncertainty comes from the carbon model underlying the methane flux modules.

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